An Optimal Decoding Strategy for Physical-Layer Network Coding Over Multipath Fading Channels

Abstract

We present an optimal decoder for physical-layer network coding (PNC) in multipath fading channels. Previous studies on PNC have largely focused on the single path case. For PNC, multipath not only introduces inter-symbol interference (ISI), but also cross-symbol interference (Cross-SI) between signals simultaneously transmitted by multiple users. To overcome these problems, the decoder at the relay of our PNC design makes use of a belief propagation (BP) algorithm to decode the multipath-distorted signals received from multiple users into a network-coded packet. We refer to our multipath decoding algorithm as MP-PNC. Our simulation results show that, benchmarked against synchronous PNC over a one-path channel, the bit error rate (BER) performance penalty of MP-PNC under a two-tap ITU channel model can be kept within 0.5 dB. Moreover, it outperforms a MUD-XOR algorithm by 3 dB (MUD-XOR decodes the individual information from both users explicitly before performing the XOR network-coding mapping). Although the framework of fadingchannel PNC presented in this paper is demonstrated based on two-path and three-path channel models, our algorithm can be extended to cases with more than three paths. Index Termsphysical-layer network coding, multipath fading, symbol misalignment, belief propagation,

Joint LDPC and physical‐layer network coding with incremental phase pre‐rotation for two‐way relaying

“…It is supposed that PLNC technique has a large potential to be applied in the next generation radio access networks. Recently, many studies have been made on the PLNC from the aspect of tackling unsatisfactory channel [1][2][3][4]. The coded modulation schemes are further considered for TWR systems in [5][6][7].…”